How does an induction generator deliver electrical power to a supply network?

An induction generator delivers electrical power to a supply network by operating in conjunction with an existing electric supply that maintains a constant voltage and frequency.1

The process functions as follows:

• Prime Mover Input: A prime mover applies torque to the induction machine, causing the rotor to spin faster than its synchronous speed (defined as $120f/p$ revolutions per minute, where $f$ is the supply frequency and $p$ is the number of poles).1
• Induced Currents: Because the rotor conductors move faster than the rotating magnetic field (the air-gap field), currents are induced within the rotor.1
• Torque and Power Delivery: These induced currents interact with the magnetic field to create a torque that balances the torque applied by the prime mover. Consequently, a stator current flows into the supply network, delivering electrical power.1

The amount of power delivered is approximately proportional to the difference between the rotor speed and the field speed, a difference typically ranging from 0.5 to 2 percent of the rated speed. Because these machines lack their own magnetic field source, they generally require connection to an established network to operate.1